Let’s Take A Drive Down Serpentine Ave

Eric Fischer points us to this 1859 Assessor’s map of Serpentine Avenue, the predecessor to Cesar Chavez nee Army. It shows lots for sale along Precita Creek, Bernal and San Jose Road. Edited verison below, original here.

That would have been a rather entertaining drive. And that little park on Coso Ave and Precita used to be a gravel pit! Typical aggressive land sales on the top of Bernal… Curious if any of the bridges were in place but just not shown on the 1857/1859 Coast Survey map.

Actually there’s another bit of Serpentine left too! If you search for Serpentine Ave on google maps, it shows you a little alleyway off of Potrero between 25th and 26th, which, based on the old maps, was originally part of Serpentine.

So my understanding is that serpentine is a type of rock that is or was plentiful in San Francisco, that Potrero Hill (or one of the Potrero hills) was composed of it. And that it is also the official rock of California.
Does any body have any more thoughts on it, and what serpentine was used for after portions of the hill/s were leveled?

Lots is still here. There’s an “archipelago” of serpentine hills running NW to SE diagonally across the city from Fort Point, through Pac Heights to Potrero, ending at Hunter’s Point. Most other hills are sandstone.

Bernal is part chert, Franciscan Complex volcanic rock, Franciscan Complex mélange, depending on what side of the hill you’re on. Most of the Mission is alluvium, while Noe and the lower part of Bernal are Hillslope Deposits (Quaternary). And the two Twin Peaks are actually different types of rock.

I am out of my depth here, and I am sure there are more common rock names to use — but you too can download the very cool USGS geological map as a Google Earth layer and pretend to know what you are talking about at your next dinner party (w00t).

Howard Street south of Duboce became South Van Ness because the area around 3rd and Howard pre-Moscone was one of the worst slums in San Francisco, which gave Howard Street a bad name. The good citizens of Howard Street in the Mission District wanted to dissociate themselves from the unseemely reference, so they petitioned to change the name of the street to South Van Ness, because Van Ness had a better rep.